1. Field of the Invention
This invention relates to a closed caption decoder, especially to a closed caption decoder equipped with a pause control function for learning languages.
2. Description of the Related Art
A closed caption system is adopted in the United States for deaf people, which displays subtitles on a screen when desired. In this system, closed caption signals are superimposed on the television signals. The closed caption signals are decoded by a closed caption decoder installed at each house thereby subtitles can be displayed on the screen of a television when desired.
The format of the closed caption signals is prescribed by the Federal Communications Commission (FCC) and according to the regulation of the FCC, display control codes indicating character information, position, color and display status are encoded in closed caption signals. Further, closed caption signals are being superimposed on more and more video software tapes and the subtitles corresponding to the closed caption recorded in the video software tapes can be displayed on a screen in the same way as that of a television.
Incidentally, a closed caption decoder is also utilized as an apparatus for learning languages in combination with a video cassette recorder by making use of the feature that subtitles are displayed on the screen of a television.
When a closed caption system is used for a language study, a caption pause function to stop displaying subtitles is necessary in order to match the speed of flowing subtitles on a screen with the speed at which a user can understand the voice from the video cassette tape. Further, for a video software tape in which the other language such as Japanese has already been superimposed on the tape, it is necessary to mask Japanese language subtitles by changing the position of the closed caption.
FIG. 6 is a block diagram showing the configuration of a conventional apparatus for studying English using a closed caption decoder. In this figure, reference numeral 100 denotes a video cassette recorder which reproduces a video software tape, 110 denotes an English learning apparatus, 111 denotes a closed caption decode circuit which performs decode processing by extracting characters to be displayed on a screen from the closed caption signals superimposed on video signals outputted from video cassette recorder 100, 112 denotes a screen display control circuit which produces image signals by superimposing the decoded characters with the image outputted from the video cassette recorder 100 and which outputs the superimposed image signals, 113 denotes a pause control circuit which provides an instruction to the closed caption decode circuit 111 that the closed caption decode circuit 111 should perform a pause operation when an image signal outputted from the video cassette recorder 100 which is in a pause operation is received, 114 denotes a display position control circuit which provides an instruction of a display position to the screen display control circuit 112 so that closed caption characters are displayed at a desired position on a screen, 120 denotes a monitor such as a Cathode Ray Tube (CRT) display.
Firstly, image signals including the data of 16 bits in every field for closed caption are outputted from the video cassette recorder 100 upon start of the reproducing operation of the video cassette recorder 100. The closed caption decode circuit 111 performs an extracting operation of the data necessary for displaying closed caption character from the superimposed data and performs a closed caption decoding operation for the extracted data. The closed caption decoded by the closed caption decode circuit 111 is sent to the screen display control circuit 112 where the closed caption is superimposed on an image signal. The resultant superimposed signals are provided to the monitor 120 where the superimposed image is displayed on a screen. When subtitles of the language other than English such as Japanese has already been superimposed on the video software tape, a user inputs a desired display position of closed caption and the input is sent to the display position control circuit 114. After that, the display position control circuit 114 instructs the screen display control circuit 112 to display the closed caption at the desired position based on the user's input.
Next, when a user pauses the video cassette recorder 100, the pause control circuit 113 detects a pause signal outputted from the video cassette recorder 100 and then instructs the closed caption decode circuit 111 to perform a pause operation of the caption decode.
However, a conventional apparatus for learning English as explained above has drawbacks that it is very difficult for a user to pause the closed caption at a desired point and that closed caption is not displayed until the rotation of the head becomes stable after the pause operation is terminated.